The quest to achieve net-zero emissions by mid-century faces a significant challenge in decarbonizing three crucial global heavy industries: steel, cement, and ammonia, which together account for around a fifth of anthropogenic CO2 emissions. These industries have relied on processes that haven’t changed much in over a century, but the growing urgency for greener solutions is shaking up the status quo.

Currently, two emerging technologies are touted as potential solutions for decarbonizing these problem industries: carbon capture and storage (CCS) and green hydrogen. However, both these technologies face criticisms and accusations of hype.

In the case of steel manufacturing, which accounts for 11% of anthropogenic CO2 emissions, possibilities to reduce these emissions include more efficient use and recycling of steel and the adoption of CCS. But the most significant gains might come from abandoning the blast furnace altogether. Direct electric current or electrolysis, fuelled by green hydrogen, is an alternative approach being explored by companies like ArcelorMittal and Tata Steel.

Ammonia fertilizer manufacturing, responsible for around 2% of anthropogenic CO2 emissions, relies on the Haber-Bosch process, which is energy-intensive and emits large amounts of CO2. To decarbonize this process, green hydrogen is seen as a potential solution, with CF Industries planning to make green hydrogen using renewable energy. Other improvements or replacements for the Haber-Bosch process are also being explored, including the use of new catalysts and an electrochemical process developed by Monash University researchers.

Portland cement, the third carbon-intensive industry, is responsible for about 8% of anthropogenic CO2 emissions. Replacing the coal used in the production process with green hydrogen could reduce emissions by about a third, but other solutions are needed to eliminate the CO2 generated by the process. Options include capturing the CO2 emissions, finding industrial uses for the CO2, and changing the raw materials used in the cement production process.

These developments point to a future where major industrial processes could be significantly less carbon-intensive. While there is still a long road ahead to fully green these industries, these emerging technologies and innovative solutions offer promising paths to achieving our global emissions goals.